William hainswobth



(No Model.)

W. HAINSWORTH.

PROCESS OF MANUFACTURING STEEL. No. 284,006. 8 Patented Aug. 28, 1883.

II "I "III IIIIIIII I III UNITED STATES P TENT Unmet.

WILLIAM HAINSWOBTH, or PITTSBURMG, PENNSYLVANIA.

-PRQCESS OF MANUFACTURING STEEL.

SPECIFICATION forming part of Letters Patent No. 284,006, dated August 28,1883.

Application filed June 9, 1882. (No model.)

.To all whom it may conga-w.-

Be it known that I, WILLIAM HAINSWORTH, of Pittsburg, county of Allegheny, State of Pennsylvania, have invented or discovered a new and useful Improvement in Processes for the Manufacture of Steel; and I do hereby declare the following to be a full, clear, concise,

and exact description thereof, reference being had to the accompanying drawings, making a part of this specification, in whichli-ke letters indicating like parts- Figure 1 represents in perspective view a Bessemer converter erected to or nearly to horizontal position, and a stirring-tool or rabble suitable for use therein, as presently to be described; and Fig. 2 is a separate view of the stirring-tool.

The use of manganese as an agent in the production of Bessemer steel at or near the close of the operation of conversion is well known in the art. Heretofore it has been usual to charge the manganese, inahot condition, or somewhat heated, directly into the con verter shortly after the cessation of the blowing operation; and in the manner in which the manganese has heretofore been thus used it has been found that in order to secure a good product the amount of manganese used to insure good chemical reaction gives in the product from eight-tenths to one per cent. of manganese.

By my improved method of operation I am enabled to secure the chemical reaction desired, and also to greatly improve the quality of the steel made, by so employing the manganese that it will be nearly all eliminated, and will leave in the steel manufactured only a small percentage-say from one-fifth to onehalf of one per cent. All this I accomplish by stirring or mixing, by the use of a suitable tool introduced through the open mouth of the converter, the manganese with the fluid metal while the latter is still in the converter, and

before pouring, substantially as hereinafter described.

In the drawings, B represents a Bessemer converter, which may be of any suitable construction, mounted in the usual way over a I pit, B

The operation of charging and treating the metal in the converter up to the cessation of the blowing operation and the introduction of spiegeleisen, if the latter be used, differs in no material respects from that already practiced in the art. While the converter still remains in the horizontal or nearly horizontal position, as indicated, the manganese is charged into the fluid metal within the converter in the usual way and to the amount of, say, about one and one-half per cent. by weight, as compared with the fluid metal. As soon as this is done, or within a very short time thereafter, the manganese and fluid metal are to be well stirred together or mixed by any suitable tool inserted through the open mouth of the converter. One such tool is shown in the drawings, which may consist of a rabble or stirring tool, a, having a long handle, a, and for convenience of manipulation suspended at or near its center of gravity by a chain, a. The head of the tool, or so much of it as will be subjected to the destructive heat employed, should be made of or coated with suitable re= fractory material, such as plumbago, the clay, &c. One, two, or more workmen then take hold of the handle a, introduce the working end or head directly through the converter: mouth into the body of the fluid metal inside, and by stirring the same back and forth effeet a rapid and thorough mixing of the man ganese with the fluid metal in the converter. The usual chemical reaction soon follows, except that when it commences it is ordinarily much more rapid and vigorous. The stirring ordinarily should be kept up until the reaction ceases, which for the average charge will be from one to two minutes.

WVhile I do not limit myself to any particular theory as regards the operation thus described, I believe it to be true that all or the greater part of the beneficial effect of the manganese on the steel results from the chemical reaction which-takes place when the two are united, and that but little, if any, improvement is effected in the product by the presence of manganese therein; hence I believe it to be true that by the mixing of the two in the manner and under the conditions described a more complete and a more uniform chemical reaction takes place, and a much larger percentage of manganese is eliminated thereby, so that in the steel product I am enabled to reduce the amount of manganese therein from about nine-tenths of one per cent., on the average, to, say, five-tenths, and even sometimes as low as two-tenths of one per cent; but whatever may be the correct theory as regards the operation described, I find the effect to be that steel thus made by mechanical mixing together of manganese and fluid steel while in a converter gives a product much more uniform in quality than has been produced heretofore without such mixing, and also that the product is better, has greater tensile strength and rolls better into finished articles, and a uniform quality of product is one of great importance, and one which in the manufacture of Bessemer steel has heretofore been exceedingly difficult of attainment, so much so that for many purposes in the art it has not given satisfactory results.

By my process I get a product which possesses the desired uniformity of quality as well as superiority of quality, and which, as above set forth, works more satisfactorily in producing manufactured articles.

As regards the tool employed in stirring, as

above described, I do not limit myself to any particular form or construction of stirring im-,

plement; nor is it essential that manual power should be employed for the purpose, as all stirring or rabble tools known in kindred branches of the art and suitable for use within a converter may be employed in the manner and for the purposes above designated.

I am aware that it is not new to rotate a converter on its axis to effect a mixing of its contents; but such rotation, as a means of doing the work above described, is too slow for the purpose of effecting the complete admixture as desired during the progress of the chemical reaction; and I am also aware that it is not new to pour the converted metal into a ladle and then stir in spiegeleisen but the object of my invention cannot be attainedwith sufficient I practical certainty and uniformity in this way,

because the converted metal necessarily becomes considerably reduced in temperature while pouring, so that it is liable to be too .loosen it, and discharge the ladle contents;

hence the present invention is limited to the operation described when performed by the introduction of a suitable stirring-tool into the fluid metal while still in the converter,

, and before pouring, substantially in the manner described.

I am aware that it is not new to stir manganese in molten metal in furnaces wherein artificial heat is employed to keep or hold the metal in the condition it then has, and while the mixing is being done; but a peculiar difficulty in the treating of Bessemer metal arises from the fact that when the converter is turned down onto its side, or into a horizontal position, the metal, not being acted on by nor being under the influence of any extraneous heat, is at once covered with a crust or layer of solid or semi-solid slag, scoria, &c., which is continually increasing, and which interferes materially with the successful application to such metal of modes of treatment known in other departments of metal-working. crust I break up, and use the stirring-tool for this purpose. I claim to have discovered and experimentally worked out to full and complete success, with the useful results above stated, the fact that in the absence of extraneous heat, and in spite of the crust, Bessemer metal can be materially improved in quality by breaking up the crust and stirring in the -manganese while the metal is still in the converter; and I further claim that this useful result was never attained in any practical senseuntil Idid it, and, in fact, that itwas unknown in the art; and it is still further true that the breaking up of the slag by the use of the stirrer permits the necessary chemical re actions to take place more freely and with greater perfection, and allows of a perfectly free escape of the gases; and, furthermore, the slag being broken up runs out freely when the steel is poured out into the ladle, and there floating on the top protects the molten steel from further loss by'oxidation; and it is a great gain to get the slag out of the converter in this way, for if it remains as an unbroken cake the molten steel runs out beneath it, leaves much of it adhering to the furnace-lining, and this being broken up and blown out at the next heat carries out from two to five times its own weight of good metal, all of which is a complete loss.

I am also aware of the use of manganese in the working of wrought-iron during the time it is subject to extraneous heat, and be-- fore the work of conversion by extraneous heat is completed, as has been done in rotary furnaces of the Dauks type; but this falls short of embodying my invention, first, in the material operated on; second, in the results produced; and, third, in the stage of the operation at which the manganese is employed; and, still further, the conditions of use with reference to which my invention is made do not exist in the revolving furnace wroughtiron process; or, in other words, the difficulties encountered in the treatment of Bessemer metal, as described, are such as do not arise in any other branch of this or the kindred arts; and the overcoming of these difficulties, along with the attaining thereby of a better product, involves, asI believe, the making of a patentable invention or discovery. 7 I claim herein as my invention In the art of making Bessemer steel, the

This

process of intimately mixing the manganese ant product is materially lessened, substanwith the molten metal, which consists in tially as described. breaking the crust formed on the surface of In testimony whereof I have hereunto set the metal, and in the prompt and rapid agimy hand.

5 tation of the metal and charge of manganese WILLIAM HAINSWORTH.

by a suitable tool While the metal is still in Witnesses: the converter, and just before pouring,where- GEORGE H. OHRIsTY, by the percentage of manganese in the result- R. H. WHITTLESEY. 

